No-Risk Blood Test for Down Syndrome

Safe Blood Test for Down Syndrome continued...

Quake's team ran the test on small blood samples from 18 pre-selected pregnant woman and a single male donor.

Some of the women had normal pregnancies. Nine of the women carried fetuses with Down syndrome. Two of the women carried fetuses with Edward syndrome (an extra copy of chromosome 18) and one woman carried a fetus with Patau syndrome (an extra copy of chromosome 13).

The score: A plus. The test detected every genetic defect and was able to identify every normal pregnancy (as well as the male donor).

"That makes us feel pretty good. But one has to reserve judgment until this can be tested in thousands of samples," Quake cautions.

"This would be a big step forward. This is exciting stuff," says J. Christopher Glantz, MD, MPH, director of the perinatal outreach program and professor of obstetrics and gynecology at the University of Rochester Medical Center, N.Y.

Glantz, who was not involved in the Quake study, agrees that the DNA test must be tested in a very large number of women. Before it's ready for prime time, researchers will have to show that it misses very few cases of Down syndrome -- and that it sounds almost no false alarms.

"If this is confirmed to be as useful as the authors say, it would be quite a significant step forward, because women would no longer have to undergo an invasive test," Glantz says.

Quake thinks the test will be able to detect Down syndrome as early as the fifth week of pregnancy. Currently, the test would cost about $700. But that cost would drop considerably if it were widely used.

"We are two to three years away from a viable test," Quake says. "This technology is not common in hospitals now, but we anticipate it will be soon. We are very excited about the prospects of improving health and saving lives."

Quake and colleagues report their findings in the Oct. 6 early online edition of the Proceedings of the National Academy of Sciences.